The present invention relates to lyophilized compositions containing sphingoglycolipid, and more particularly to lyophilized compositions containing sphingoglycolipid, in which the sphingoglycolipids intrinsically having low or little solubility into water have been improved in their solubility into water, and the process for preparing them.
xcex1-sphingoglycolipids exhibit a variety of useful physiological activities in body, and may be used for numerous medical agents such as anti-tumor agents, immunostimulators, and bone marrow cell proliferating promoters.
Amongst the sphingoglycolipids, most of the ones comprising monosaccharide as the sugar moiety are of low or little solubility in water. Various methods have been examined in order to improve the solubility of such sphingoglycolipids, resulting in unsatisfactory solubility. There is a problem in these methods that solution of the sphingoglycolipids in water preciptates during their storage thereby decreasing the solubility with the passage of time.
In view of such circumstances as above, the object of the present invention is to provide a lyophilized composition comprising a low or little soluble sphingoglycolipid sugar moiety of which is composed of a monosaccharide and maintaining a high re-solubility even after storage for a long period.
The present inventors have found that when a sphingoglycolipid ((xcex1-glycosylceramide) which has xcex1-glycosyl linkage structure comprising a monosaccharide as a sugar moiety and a low solubility in water was lyophilized after incorporation to be dissolved in a solvent together with a polyoxysorbitan fatty acid ester and sucrose (white sugar), mannitol or glucose, or alternatively further comprising sodium deoxycholate or histidine, the composition has an extremely high re-solubility still after storage for a long period. The present invention has been accomplished on the basis of the finding.
That is to say, the present invention relates to a lyophilized composition comprising the xcex1-glycosylceramide as an active ingredient represented by the following formula (A) or a salt thereof, a polyoxysorbitan fatty acid ester and sucrose, mannitol or glucose, or alternatively further comprising sodium deoxycholate or histidine: 
wherein
R1-R9 and X represent a particular group and an integer in the particular range described hereinafter, respectively.
The present invention also relates to a process for preparing the lyophilized composition which comprises dissolving the components incorporated in the composition in a heated aqueous solvent, cooling and then subjecting the solution to the step of lyophilization.